1. Field
Various embodiments are directed to methods and apparatus for wireless communication and, more particularly, to methods and apparatus related to peer-to-peer communications.
2. Background
In a wireless network, in which a network infrastructure does not exist, such as an ad hoc peer-to-peer network, a terminal is faced with a number of challenges when establishing a communication link with another peer terminal. One challenge is that when a terminal just powers up or moves into a new area, the terminal may have to first find out whether another terminal is present in the vicinity before any communication between the two terminals can start.
The general solution to the above problem of identification and acquisition is to let the terminal transmit and/or receive signals according to a communication protocol. However, an ad hoc network presents a number of challenges. Often the terminals may not have a common timing reference, e.g., because of the lack of the network infrastructure. As such, it is possible that when a first terminal is transmitting a signal and a second terminal is not in the receiving mode, the transmitted signal does not help the second terminal to detect the presence of the first terminal.
Significantly, power efficiency has a great impact on the battery life of the wireless terminals and thus presents another challenge in wireless systems. Existing peer-to-peer systems typically employ a simple fixed power arrangement for simplicity. Under such an arrangement, a transmitter uses a fixed traffic transmission power regardless of the distance of the intended receiver and the channel condition. A fixed power system, however, suffers from poor power efficiency and reduced overall throughput due to signal interference.
Additionally, a plurality of wireless terminals may operate in an environment while sharing a frequency spectrum to establish ad hoc peer-to-peer communications. Because such ad hoc peer-to-peer communications are not centrally managed by a centralized controller, interference between multiple peer-to-peer links among nearby wireless terminals is problem.
Consequently, a way is needed to schedule and/or prioritize ad hoc peer-to-peer communication links among different wireless terminals without the assistance of a centralized controller.